package com.tfswx.ruleengine.compute.util.sm4;

import lombok.extern.slf4j.Slf4j;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

@Slf4j
class InnerSM4Stream {
    /**
     * 加密模式
     */
    public static final int SM4_ENCRYPT = 1;

    /**
     * 解密模式
     */
    public static final int SM4_DECRYPT = 0;

    private static long GET_ULONG_BE(byte[] b, int i) {
        return (long) (b[i] & 0xff) << 24 | (long) ((b[i + 1] & 0xff) << 16) | (long) ((b[i + 2] & 0xff) << 8) | (long) (b[i + 3] & 0xff) & 0xffffffffL;
    }

    private static void PUT_ULONG_BE(long n, byte[] b, int i) {
        b[i] = (byte) (int) (0xFF & n >> 24);
        b[i + 1] = (byte) (int) (0xFF & n >> 16);
        b[i + 2] = (byte) (int) (0xFF & n >> 8);
        b[i + 3] = (byte) (int) (0xFF & n);
    }

    private static long SHL(long x, int n) {
        return (x & 0xFFFFFFFF) << n;
    }

    private static long ROTL(long x, int n) {
        return SHL(x, n) | x >> (32 - n);
    }

    private static void SWAP(long[] sk, int i) {
        long t = sk[i];
        int index = 31 - i;
        sk[i] = sk[index];
        sk[index] = t;
    }

    private static final byte[] SboxTable = {(byte) 0xd6, (byte) 0x90, (byte) 0xe9, (byte) 0xfe,
            (byte) 0xcc, (byte) 0xe1, 0x3d, (byte) 0xb7, 0x16, (byte) 0xb6,
            0x14, (byte) 0xc2, 0x28, (byte) 0xfb, 0x2c, 0x05, 0x2b, 0x67,
            (byte) 0x9a, 0x76, 0x2a, (byte) 0xbe, 0x04, (byte) 0xc3,
            (byte) 0xaa, 0x44, 0x13, 0x26, 0x49, (byte) 0x86, 0x06,
            (byte) 0x99, (byte) 0x9c, 0x42, 0x50, (byte) 0xf4, (byte) 0x91,
            (byte) 0xef, (byte) 0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43,
            (byte) 0xed, (byte) 0xcf, (byte) 0xac, 0x62, (byte) 0xe4,
            (byte) 0xb3, 0x1c, (byte) 0xa9, (byte) 0xc9, 0x08, (byte) 0xe8,
            (byte) 0x95, (byte) 0x80, (byte) 0xdf, (byte) 0x94, (byte) 0xfa,
            0x75, (byte) 0x8f, 0x3f, (byte) 0xa6, 0x47, 0x07, (byte) 0xa7,
            (byte) 0xfc, (byte) 0xf3, 0x73, 0x17, (byte) 0xba, (byte) 0x83,
            0x59, 0x3c, 0x19, (byte) 0xe6, (byte) 0x85, 0x4f, (byte) 0xa8,
            0x68, 0x6b, (byte) 0x81, (byte) 0xb2, 0x71, 0x64, (byte) 0xda,
            (byte) 0x8b, (byte) 0xf8, (byte) 0xeb, 0x0f, 0x4b, 0x70, 0x56,
            (byte) 0x9d, 0x35, 0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, (byte) 0xd1,
            (byte) 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, (byte) 0x87,
            (byte) 0xd4, 0x00, 0x46, 0x57, (byte) 0x9f, (byte) 0xd3, 0x27,
            0x52, 0x4c, 0x36, 0x02, (byte) 0xe7, (byte) 0xa0, (byte) 0xc4,
            (byte) 0xc8, (byte) 0x9e, (byte) 0xea, (byte) 0xbf, (byte) 0x8a,
            (byte) 0xd2, 0x40, (byte) 0xc7, 0x38, (byte) 0xb5, (byte) 0xa3,
            (byte) 0xf7, (byte) 0xf2, (byte) 0xce, (byte) 0xf9, 0x61, 0x15,
            (byte) 0xa1, (byte) 0xe0, (byte) 0xae, 0x5d, (byte) 0xa4,
            (byte) 0x9b, 0x34, 0x1a, 0x55, (byte) 0xad, (byte) 0x93, 0x32,
            0x30, (byte) 0xf5, (byte) 0x8c, (byte) 0xb1, (byte) 0xe3, 0x1d,
            (byte) 0xf6, (byte) 0xe2, 0x2e, (byte) 0x82, 0x66, (byte) 0xca,
            0x60, (byte) 0xc0, 0x29, 0x23, (byte) 0xab, 0x0d, 0x53, 0x4e, 0x6f,
            (byte) 0xd5, (byte) 0xdb, 0x37, 0x45, (byte) 0xde, (byte) 0xfd,
            (byte) 0x8e, 0x2f, 0x03, (byte) 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b,
            0x51, (byte) 0x8d, 0x1b, (byte) 0xaf, (byte) 0x92, (byte) 0xbb,
            (byte) 0xdd, (byte) 0xbc, 0x7f, 0x11, (byte) 0xd9, 0x5c, 0x41,
            0x1f, 0x10, 0x5a, (byte) 0xd8, 0x0a, (byte) 0xc1, 0x31,
            (byte) 0x88, (byte) 0xa5, (byte) 0xcd, 0x7b, (byte) 0xbd, 0x2d,
            0x74, (byte) 0xd0, 0x12, (byte) 0xb8, (byte) 0xe5, (byte) 0xb4,
            (byte) 0xb0, (byte) 0x89, 0x69, (byte) 0x97, 0x4a, 0x0c,
            (byte) 0x96, 0x77, 0x7e, 0x65, (byte) 0xb9, (byte) 0xf1, 0x09,
            (byte) 0xc5, 0x6e, (byte) 0xc6, (byte) 0x84, 0x18, (byte) 0xf0,
            0x7d, (byte) 0xec, 0x3a, (byte) 0xdc, 0x4d, 0x20, 0x79,
            (byte) 0xee, 0x5f, 0x3e, (byte) 0xd7, (byte) 0xcb, 0x39, 0x48};

    private static final int[] FK = {0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc};

    private static final int[] CK = {0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
            0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
            0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
            0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
            0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
            0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
            0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
            0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279};

    private static byte sm4Sbox(byte inch) {
        return SboxTable[inch & 0xFF];
    }

    private static long sm4Lt(long ka) {

        byte[] a = new byte[4];
        PUT_ULONG_BE(ka, a, 0);
        a[0] = sm4Sbox(a[0]);
        a[1] = sm4Sbox(a[1]);
        a[2] = sm4Sbox(a[2]);
        a[3] = sm4Sbox(a[3]);
        long bb = GET_ULONG_BE(a, 0);
        return bb ^ ROTL(bb, 2) ^ ROTL(bb, 10) ^ ROTL(bb, 18) ^ ROTL(bb, 24);
    }

    private static long sm4F(long x0, long x1, long x2, long x3, long rk) {
        return x0 ^ sm4Lt(x1 ^ x2 ^ x3 ^ rk);
    }

    private static long sm4CalciRK(long ka) {

        byte[] a = new byte[4];
        PUT_ULONG_BE(ka, a, 0);
        a[0] = sm4Sbox(a[0]);
        a[1] = sm4Sbox(a[1]);
        a[2] = sm4Sbox(a[2]);
        a[3] = sm4Sbox(a[3]);
        long bb = GET_ULONG_BE(a, 0);
        return bb ^ ROTL(bb, 13) ^ ROTL(bb, 23);
    }

    private static void sm4_setkey(long[] SK, byte[] key) {

        long[] MK = new long[4];
        long[] k = new long[36];

        MK[0] = GET_ULONG_BE(key, 0);
        MK[1] = GET_ULONG_BE(key, 4);
        MK[2] = GET_ULONG_BE(key, 8);
        MK[3] = GET_ULONG_BE(key, 12);
        k[0] = MK[0] ^ (long) FK[0];
        k[1] = MK[1] ^ (long) FK[1];
        k[2] = MK[2] ^ (long) FK[2];
        k[3] = MK[3] ^ (long) FK[3];
        for (int i = 0; i < 32; i++) {
            k[(i + 4)] = (k[i] ^ sm4CalciRK(k[(i + 1)] ^ k[(i + 2)] ^ k[(i + 3)] ^ (long) CK[i]));
            SK[i] = k[(i + 4)];
        }
    }

    public static void sm4_one_round(long[] sk, byte[] input, byte[] output) {

        long[] ulbuf = new long[36];

        ulbuf[0] = GET_ULONG_BE(input, 0);
        ulbuf[1] = GET_ULONG_BE(input, 4);
        ulbuf[2] = GET_ULONG_BE(input, 8);
        ulbuf[3] = GET_ULONG_BE(input, 12);
        for (int i = 0; i < 32; i++) {
            ulbuf[(i + 4)] = sm4F(ulbuf[i], ulbuf[(i + 1)], ulbuf[(i + 2)], ulbuf[(i + 3)], sk[i]);
        }
        PUT_ULONG_BE(ulbuf[35], output, 0);
        PUT_ULONG_BE(ulbuf[34], output, 4);
        PUT_ULONG_BE(ulbuf[33], output, 8);
        PUT_ULONG_BE(ulbuf[32], output, 12);
    }

    private static byte[] padding(byte[] input, int mode) {
        if (input == null) {
            return null;
        }

        byte[] ret;
        if (mode == SM4_ENCRYPT) {
            int p = 16 - input.length % 16;
            ret = new byte[input.length + p];
            System.arraycopy(input, 0, ret, 0, input.length);
            for (int i = 0; i < p; i++) {
                ret[input.length + i] = (byte) p;
            }
        } else if (mode == SM4_DECRYPT) {
            int p = input[input.length - 1];
            ret = new byte[input.length - p];
            System.arraycopy(input, 0, ret, 0, input.length - p);
        } else {
            throw new RuntimeException("不支持的操作类型：" + mode);
        }
        return ret;
    }

    public static void paddingByteArray16(byte[] input16, int inputLength) {
        int paddingCount = getEncryptPaddingCount(inputLength);
        byte paddingByte = (byte) paddingCount;
        for (int i = 16 - paddingCount; i < 16; i++) {
            input16[i] = paddingByte;
        }
    }

    private static void noPaddingByteArray16(byte[] input16, int inputLength) {
        int paddingCount = getEncryptPaddingCount(inputLength);
        for (int i = 16 - paddingCount; i < 16; i++) {
            input16[i] = 0;
        }
    }

    private static int getEncryptPaddingCount(int inputLength) {
        return 16 - inputLength % 16;
    }

    public static void sm4_setkey_enc(InnerSM4_Context ctx, byte[] key) {
        if (ctx == null) {
            throw new RuntimeException("ctx is null!");
        }

        if (key == null || key.length != 16) {
            throw new RuntimeException("key error!");
        }

        ctx.mode = SM4_ENCRYPT;
        sm4_setkey(ctx.sk, key);
    }

    public static void sm4_setkey_dec(InnerSM4_Context ctx, byte[] key) {
        if (ctx == null) {
            throw new RuntimeException("ctx is null!");
        }

        if (key == null || key.length != 16) {
            throw new RuntimeException("key error!");
        }

        ctx.mode = SM4_DECRYPT;
        sm4_setkey(ctx.sk, key);
        for (int i = 0; i < 16; i++) {
            SWAP(ctx.sk, i);
        }
    }

    @Deprecated
    public static byte[] sm4_crypt_ecb(InnerSM4_Context ctx, byte[] input)
            throws IOException {
        if (input == null) {
            throw new RuntimeException("input is null!");
        }

        if ((ctx.isPadding) && (ctx.mode == SM4_ENCRYPT)) {
            input = padding(input, SM4_ENCRYPT);
        }

        int length = input.length;
        ByteArrayInputStream bins = new ByteArrayInputStream(input);
        ByteArrayOutputStream bous = new ByteArrayOutputStream();
        for (; length > 0; length -= 16) {
            byte[] in = new byte[16];
            byte[] out = new byte[16];
            bins.read(in);
            sm4_one_round(ctx.sk, in, out);
            bous.write(out);
        }

        byte[] output = bous.toByteArray();
        if (ctx.isPadding && ctx.mode == SM4_DECRYPT) {
            output = padding(output, SM4_DECRYPT);
        }
        bins.close();
        bous.close();
        return output;
    }

    @Deprecated
    public static byte[] sm4_crypt_cbc(InnerSM4_Context ctx, byte[] iv, byte[] input)
            throws IOException {
        if (iv == null || iv.length != 16) {
            throw new RuntimeException("iv error!");
        }

        if (input == null) {
            throw new RuntimeException("input is null!");
        }

        if (ctx.isPadding && ctx.mode == SM4_ENCRYPT) {
            long start = System.currentTimeMillis();
            input = padding(input, SM4_ENCRYPT);
            long end = System.currentTimeMillis();
            log.info("将byte数组填充花费：{}", (end - start));
        }

        int i = 0;
        int length = input.length;
        ByteArrayInputStream bins = new ByteArrayInputStream(input);
        ByteArrayOutputStream bous = new ByteArrayOutputStream();

        long start = System.currentTimeMillis();
        if (ctx.mode == SM4_ENCRYPT) {
            for (; length > 0; length -= 16) {
                byte[] in = new byte[16];
                byte[] out = new byte[16];
                byte[] out1 = new byte[16];

                bins.read(in);
                for (i = 0; i < 16; i++) {
                    out[i] = ((byte) (in[i] ^ iv[i]));
                }
                sm4_one_round(ctx.sk, out, out1);
                System.arraycopy(out1, 0, iv, 0, 16);
                bous.write(out1);
            }
        } else {
            byte[] temp = new byte[16];
            for (; length > 0; length -= 16) {
                byte[] in = new byte[16];
                byte[] out = new byte[16];
                byte[] out1 = new byte[16];

                bins.read(in);
                System.arraycopy(in, 0, temp, 0, 16);
                sm4_one_round(ctx.sk, in, out);
                for (i = 0; i < 16; i++) {
                    out1[i] = ((byte) (out[i] ^ iv[i]));
                }
                System.arraycopy(temp, 0, iv, 0, 16);
                bous.write(out1);
            }
        }

        byte[] output = bous.toByteArray();
        if (ctx.isPadding && ctx.mode == SM4_DECRYPT) {
            output = padding(output, SM4_DECRYPT);
        }
        long end = System.currentTimeMillis();
        log.info("将byte数组进行加解密花费：{}", (end - start));
        bins.close();
        bous.close();
        return output;
    }

    public static void sm4_crypt_cbc(InnerSM4_Context ctx, String srcFilePathString, String destFilePathString)
            throws IOException {
        sm4_crypt_cbc(ctx, Paths.get(srcFilePathString), destFilePathString);
    }

    public static void sm4_crypt_cbc(InnerSM4_Context ctx, Path srcFilePath, String destFilePathString)
            throws IOException {
        sm4_crypt_cbc(ctx, srcFilePath, Paths.get(destFilePathString));
    }

    public static void sm4_crypt_cbc(InnerSM4_Context ctx, Path srcFilePath, Path destFilePath)
            throws IOException {
        try (InputStream inputStream = Files.newInputStream(srcFilePath)) {
            sm4_crypt_cbc(ctx, inputStream, destFilePath);
        }
    }

    public static void sm4_crypt_cbc(InnerSM4_Context ctx, InputStream srcInputStream, String destFilePathString)
            throws IOException {
        sm4_crypt_cbc(ctx, srcInputStream, Paths.get(destFilePathString));
    }

    public static void sm4_crypt_cbc(InnerSM4_Context ctx, InputStream srcInputStream, Path destFilePath)
            throws IOException {
        File destFile = destFilePath.toFile();
        if (destFile.exists()) {
            destFile.delete();
        } else {
            File destFolder = destFile.getParentFile();
            if (!destFolder.exists()) {
                destFolder.mkdirs();
            }
        }
        destFile.createNewFile();

        try (OutputStream destOutputStream = Files.newOutputStream(destFilePath)) {
            sm4_crypt_cbc(ctx, srcInputStream, destOutputStream);
        }
    }

    public static void sm4_crypt_cbc(InnerSM4_Context ctx, InputStream srcInputStream, OutputStream destOutputStream)
            throws IOException {

        // 为了提升加解密的速度，检测如果发现输入流不是缓冲类型和内存流，则尝试将流包裹一层
        boolean inputIsNotBuffered = !BufferedInputStream.class.isAssignableFrom(srcInputStream.getClass())
                && !ByteArrayInputStream.class.isAssignableFrom(srcInputStream.getClass());
        boolean outputIsNotBuffered = !BufferedOutputStream.class.isAssignableFrom(destOutputStream.getClass())
                && !ByteArrayOutputStream.class.isAssignableFrom(destOutputStream.getClass());

        if (inputIsNotBuffered && outputIsNotBuffered) {
            try (BufferedInputStream inputBuffered = new BufferedInputStream(srcInputStream);
                 BufferedOutputStream outputBuffered = new BufferedOutputStream(destOutputStream)) {
                if (ctx.mode == SM4_ENCRYPT) {
                    sm4_crypt_cbc_encrypt(ctx, inputBuffered, outputBuffered);
                } else {
                    sm4_crypt_cbc_decrypt(ctx, inputBuffered, outputBuffered);
                }
            }
        } else if (inputIsNotBuffered) {
            try (BufferedInputStream inputBuffered = new BufferedInputStream(srcInputStream)) {
                if (ctx.mode == SM4_ENCRYPT) {
                    sm4_crypt_cbc_encrypt(ctx, inputBuffered, destOutputStream);
                } else {
                    sm4_crypt_cbc_decrypt(ctx, inputBuffered, destOutputStream);
                }
            }
        } else if (outputIsNotBuffered) {
            try (BufferedOutputStream outputBuffered = new BufferedOutputStream(destOutputStream)) {
                if (ctx.mode == SM4_ENCRYPT) {
                    sm4_crypt_cbc_encrypt(ctx, srcInputStream, outputBuffered);
                } else {
                    sm4_crypt_cbc_decrypt(ctx, srcInputStream, outputBuffered);
                }
            }
        } else {
            // 都是缓冲区类型流
            if (ctx.mode == SM4_ENCRYPT) {
                sm4_crypt_cbc_encrypt(ctx, srcInputStream, destOutputStream);
            } else {
                sm4_crypt_cbc_decrypt(ctx, srcInputStream, destOutputStream);
            }
        }
    }

    private static void sm4_crypt_cbc_encrypt(InnerSM4_Context ctx, InputStream input, OutputStream output)
            throws IOException {

        byte[] in = new byte[16];
        byte[] out = new byte[16];
        byte[] out1 = new byte[16];
        byte[] iv = new byte[16];

        System.arraycopy(ctx.ivBytes, 0, iv, 0, 16);

        int inputLength = 0;
        int readCount;
        while (true) {
            readCount = input.read(in);
            if (readCount > 0) {
                inputLength += readCount;
            }

            if (readCount != 16) {
                if (ctx.isPadding) {
                    paddingByteArray16(in, inputLength);
                } else if (readCount <= 0) {
                    // 上一轮已经读完，模式又是不填充
                    return;
                } else {
                    // 本轮读完，但是不够16位，模式又是不填充，需要将后续的置为0
                    noPaddingByteArray16(in, inputLength);
                }
            }

            for (int i = 0; i < 16; i++) {
                out[i] = ((byte) (in[i] ^ iv[i]));
            }
            sm4_one_round(ctx.sk, out, out1);
            System.arraycopy(out1, 0, iv, 0, 16);
            output.write(out1);

            if (readCount != 16) {
                return;
            }
        }
    }

    private static void sm4_crypt_cbc_decrypt(InnerSM4_Context ctx, InputStream input, OutputStream output)
            throws IOException {

        byte[] in = new byte[16];

        int readCount;

        // 第一段
        try {
            readCount = input.read(in);
        } catch (IOException e) {
            throw e;
        }
        if (readCount <= 0) {
            // 没数据
            throw new RuntimeException("数据为空");
        }

        byte[] out = new byte[16];
        byte[] out1 = new byte[16];
        byte[] temp = new byte[16];
        byte[] iv = new byte[16];

        System.arraycopy(ctx.ivBytes, 0, iv, 0, 16);

        if (readCount < 16) {
            // 总数据长度小于16，已经结束，需要将不够16位的后面都置为0
            for (int i = 16 - readCount; i < 16; i++) {
                in[i] = 0;
            }
            sm4_one_round(ctx.sk, in, out);
            for (int i = 0; i < 16; i++) {
                out1[i] = ((byte) (out[i] ^ iv[i]));
            }

            // 第一段就处理完成了
            if (ctx.isPadding) {
                // 填充模式，需要去掉后面填充的部分
                int paddingCount = out1[out1.length - 1];
                int beforeLength = 16 - paddingCount;
                if (beforeLength > 0) {
                    output.write(out1, 0, beforeLength);
                }
            } else {
                output.write(out1);
            }

            return;
        } else {
            // 把第一段处理了，再执行后续的
            System.arraycopy(in, 0, temp, 0, 16);
            sm4_one_round(ctx.sk, in, out);
            for (int i = 0; i < 16; i++) {
                out1[i] = ((byte) (out[i] ^ iv[i]));
            }
            System.arraycopy(temp, 0, iv, 0, 16);
        }

        while (true) {
            readCount = input.read(in);

            if (readCount == 16) {
                // 刚好16位
                // 先把之前的写入
                output.write(out1);

                System.arraycopy(in, 0, temp, 0, 16);
                sm4_one_round(ctx.sk, in, out);
                for (int i = 0; i < 16; i++) {
                    out1[i] = ((byte) (out[i] ^ iv[i]));
                }
                System.arraycopy(temp, 0, iv, 0, 16);
                // 继续下一段读取
                continue;
            }

            if (readCount <= 0) {
                // 上一轮刚好读完
                if (ctx.isPadding) {
                    // 填充模式，去掉之前数据中，填充的部分，将有效部分数据写入输出流(长度大于0才写)，然后直接结束
                    int paddingCount = out1[out1.length - 1];
                    int beforeLength = 16 - paddingCount;
                    if (beforeLength > 0) {
                        output.write(out1, 0, beforeLength);
                    }
                }

                return;
            } else if (readCount < 16) {
                // 本轮读取完毕，先把之前的写入
                output.write(out1);
                // 本轮读取完毕，但是不够16位，将读取部分的后续置为0
                for (int i = 16 - readCount; i < 16; i++) {
                    in[i] = 0;
                }
                sm4_one_round(ctx.sk, in, out);
                for (int i = 0; i < 16; i++) {
                    out1[i] = ((byte) (out[i] ^ iv[i]));
                }
                if (ctx.isPadding) {
                    // 填充模式，需要去掉后面填充的部分
                    int paddingCount = out1[out1.length - 1];
                    int beforeLength = 16 - paddingCount;
                    if (beforeLength > 0) {
                        output.write(out1, 0, beforeLength);
                    }
                } else {
                    output.write(out1);
                }

                return;
            }
        }
    }
}
